1211011220 has 24 divisors (see below), whose sum is σ = 2543837184. Its totient is φ = 484268576.

The previous prime is 1211011211. The next prime is 1211011237. The reversal of 1211011220 is 221101121.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 95789 + ... + 107691.

It is an arithmetic number, because the mean of its divisors is an integer number (105993216).

Almost surely, 2^1211011220 is an apocalyptic number.

1211011220 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

1211011220 is an abundant number, since it is smaller than the sum of its proper divisors (1332825964).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

1211011220 is a wasteful number, since it uses less digits than its factorization.

1211011220 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 16999 (or 16997 counting only the distinct ones).

The product of its (nonzero) digits is 8, while the sum is 11.

The square root of 1211011220 is about 34799.5864917961. The cubic root of 1211011220 is about 1065.8990021260.

Adding to 1211011220 its reverse (221101121), we get a palindrome (1432112341).

The spelling of 1211011220 in words is "one billion, two hundred eleven million, eleven thousand, two hundred twenty".